The QNBBM Active balancer 1S series is no limitation for using on big voltage battery pack whatever it is 100V 200V 300V 400V or 600V, 800V, or more. If the single cell voltage is 3.2V, then the 600V lifepo4 battery pack series by 200 string cells will need to use 200pcs 1S QNBBM active balancers to work. 1S 2.0V 2.3V 2.4V 3.2V 3.7V 4.2V 4.3V Active Balancer Battery Equalizer For Lithium Polymer, LTO, 2.0V Lead Acid/Vrla Battery, LiFePO4 and Li-ion 18650 DIY Active Balancer